It is well known that a reinforcement panel such as a backboard is joined to and arranged on the rear face of a body panel in the attachment structure for an in-vehicle component, such as a wiper motor to be attached to the body panel, in order to improve the supporting strength of the in-vehicle component to the body panel. Attachment of the in-vehicle component to the body panel is carried out by passing a fastening member such as a bolt through the in-vehicle component, the body panel, and the reinforcement panel in a state where the body panel is sandwiched between the attaching portion of the in-vehicle component and the reinforcement panel.    Patent Document 1: JP-A 2000-233720